As a conventional fluid-related function device connected to a pipe of a fluid circuit through which fluid such as refrigerant flows, there is a pressure switch disclosed in Patent Literature 1 for example. As shown in FIG. 16, the conventional pressure switch 801 includes a joint 810 made of brass and a lid member 820 made of stainless steel. The joint 810 and the lid member 820 are diffusion bonded to each other by projection-welding (resistance-welding). The joint 810 is connected to a pipe of a fluid circuit (not shown), and fluid is introduced into the lid member 820 through an interior hole 812 in a central portion of the joint 810 and a through hole 822 of the lid member 820.
The pressure switch 801 is provided with an outer projection 815 (projection) and an inner projection 816 for projection-welding. Spatters generated when the outer projection 815 is bonded to the lid member 820 by the projection-welding are trapped in a space formed between the outer projection 815 and the inner projection 816.
The pressure switch 801 is formed such that a projecting height of the inner projection 816 is lower than that of the outer projection 815 and a gap is provided between the inner projection 816 and the lid member 820 so that the inner projection 816 is not welded together with the outer projection 815 when the projection-welding is carried out. However, if this gap is large, there is fear that spatters to be trapped in the space flow out into the pipe, and if the gap is small, there is fear that the inner projection 816 is welded and spatters generated at that time flow out into the pipe and there is a problem that it is difficult to adjust the gap.
As a structure to solve such a problem, the following structure can be considered.
A pressure switch 901 shown in FIG. 17 includes a joint 910 made of brass and a cap member 920 made of stainless steel. The joint 910 has a flat surface 912. The flat surface 912 includes a cylindrical portion 913 which is in communication with a continuity passage 911b, and an annular chevron-shaped projection 917 which is placed coaxially with the cylindrical portion 913 and which is projection-welded to the cap member 920. An inner hole 924 into which the cylindrical portion 913 is inserted opens from a center of the cap member 920.
The joint 910 and the cap member 920 are assembled as follows. First, the cylindrical portion 913 of the joint 910 is inserted into the inner hole 924 of the cap member 920 and in this state, the projection 917 of the joint 910 and the cap member 920 are bonded to each other through projection-welding. A load is outwardly applied to a peripheral edge 915 of the inner hole 914 of the cylindrical portion 913 centering on an axis L, and the peripheral edge 915 is crimped such that the peripheral edge 915 is superposed, over its entire periphery, on an a peripheral edge 925 of the inner hole 924 of the cap member 920.
According to this, spatters generated when the joint 910 and the cap member 920 are projection-welded to each other are stored in a space β between the joint 910 and the cap member 920 inside the annular projection 917, and since the peripheral edge 915 of the cylindrical portion 913 is crimped by the peripheral edge 925, the spatters are trapped in the space β. Hence, at the time of actual operation when the pressure switch 901 is connected to a pipe of a fluid circuit, it is possible to restrain spatters from flowing out into the fluid circuit.